arch/arm-all/arm-aeabi/ldiv.c

   1 /*
   2     Copyright © 2009-2014, The AROS Development Team. All rights reserved.
   3     $Id$
   4 */
   5
   6 #include <inttypes.h>
   7
   8 void __attribute__((noreturn)) __aeabi_ldiv0(uint64_t);
   9
  10 int64_t __ldiv(int64_t a, int64_t b)
  11 {
  12         int32_t sign = ((int32_t)(a >> 32))^((int32_t)(b >> 32));
  13         int64_t ret = 0;
  14
  15         if (a < 0)
  16                 a = -a;
  17         if (b < 0)
  18                 b = -b;
  19
  20         if (b == 0)
  21         {
  22                 __aeabi_ldiv0(a);
  23         }
  24         else if (b > a)
  25         {
  26                 return 0;
  27         }
  28         else
  29         {
  30                 int first_bit_a = __builtin_clz(a >> 32);
  31                 int first_bit_b = __builtin_clz(b >> 32);
  32
  33                 if (first_bit_a == 32)
  34                     first_bit_a += __builtin_clz(a & 0xffffffff);
  35                 if (first_bit_b == 32)
  36                     first_bit_b += __builtin_clz(b & 0xffffffff);
  37
  38                 uint64_t mask = 0x00000001ULL << (first_bit_b-first_bit_a);
  39                 b <<= (first_bit_b - first_bit_a);
  40
  41                 do
  42                 {
  43                         if (a >= b)
  44                         {
  45                                 ret |= mask;
  46                                 a -= b;
  47                         }
  48
  49                         mask >>=1;
  50                         b >>=1;
  51                 } while(mask);
  52         }
  53
  54         if (sign < 0)
  55                 ret = -ret;
  56
  57         return ret;
  58 }
  59
  60 int64_t __ldivmod_helper(int64_t a, int64_t b, int64_t *remainder)
  61 {
  62         int64_t quotient;
  63
  64         quotient = __ldiv(a, b);
  65
  66         *remainder = a - b * quotient;
  67
  68         return quotient;
  69 }